Severus Snape is best known as the Head of Slytherin House and Potions Professor at Hogwarts during Harry Potter's time at school. He also taught Defense Against the Dark Arts for one year. He was born on 9 January 1960 and died on 2 May 1998 at age 38.
He is described as a batlike, greasy, hooked-nosed man – sometimes hovering ominously like a vulture over certain unfortunate students. In the bookverse, he is coldly angry and mean to most of his students, and especially to Harry Potter. In the early books, he was a red-herring 'villain' that young Harry and his friends were suspicious of. His character was later expanded to reveal that he has a long-standing hatred and resentment of his childhood, and anything that reminds him of it is an object of his ire. His history very much defines him.
Snape is a Death Eater and a double agent for Voldemort and Dumbledore. He is a master of Occlumency, which allows him to keep Voldemort from discovering his act and killing him. He is also a talented Legilimens, and his black, penetrating stare may in fact allow him to see into people's unguarded minds, as Harry suspects more than once. Snape is also a gifted wizard in other ways. He is capable of brewing fiendishly difficult potions such as Veritaserum and the Wolfsbane Potion that allows werewolves to keep their human minds when they transform; he has also created new spells, including his signature curse, Sectumsempra, and its counterspell; and he can perform wandless and nonverbal magic. Sadly, his brilliance is never allowed to shine through his brooding anger.
Severus Snape is the son of Tobias Snape, a Muggle, and Eileen Prince, a witch. His was a poor and unhappy home, and he deeply resented his Muggle father despite being neglected by both parents. In school, he secretly styled himself the 'Half-Blood Prince', curiously acknowledging his mixed heritage and scorning the part he disliked at the same time. No one besides himself ever seems to have called him that, though.
He was close friends with Lily Evans in childhood and had a one-sided crush on her that developed into enduring love. Both were intelligent and talented potioneers. However, as Snape became more involved with the Dark Arts and the future Death Eaters who were his other school friends, he pushed Lily away. The final straw was when he slipped and called her a Mudblood in a moment of anger. He apologised, but the damage had been done, and she wouldn't forgive him for making her the exception to his prejudice.
Snape hates all of the Marauders because they teased and tormented him throughout his school years. He especially hates James Potter because James was the most cruel to him: he humiliated Snape (not least by once saving his life) and he managed to marry the woman Snape loved.
His resentments led him to join Voldemort as a Death Eater upon leaving school, but he came to regret that decision when Voldemort murdered Lily Evans, believing her son Harry was the subject of a prophecy foretelling his defeat. Racked with grief, he came to Dumbledore's side and served from then on as a double agent. He respects Dumbledore enough to do just about anything at the Headmaster's request, no matter how much he dislikes it.
Snape is the head of Slytherin House for Harry Potter's first six years at Hogwarts and is ruthlessly biased in favor of his house. He dislikes Gryffindors in general and will even abstain from giving Hermione Granger points for brilliance. He is mean to Neville Longbottom because Neville is bad at potions and because, had Neville been the subject of the prophecy, Lily Evans would have survived.
As alluded to above, Snape resents Harry Potter for being James' son. Most of the time, he seems to regard Harry as a nasty little carbon-copy of his father and takes out his hatred of James on Harry. However, he also protects Harry from any serious danger, because he is Lily's son.
In canon, he is short-tempered, callous, and cruel, but not quite full-blown evil. Some writers like to make him evil to bully another character, possibly making them a woobie. More often, though, fandom takes a different view.
Snape is popular. Really popular. Popular to the point of being one of the most likely characters for a Sue-wraith to possess. For some reason, despite his greasy appearance and cold demeanor (and possibly because of Alan Rickman), he is portrayed as a memetic sex god. He is paired with everybody. Everybody. Even when it is really, really creepy.
One of his more popular pairings is with Hermione Granger. This can be done well on the basis that they are both brilliant, but overlooked and often outsiders even among friends, and thus have reason to understand each other. It's difficult to pull off, though, because canon!Snape never shows the least sign of trying to understand anyone, not even himself. It is infinitely more difficult to pull off if Hermione is underage at the time of the fic, because gah.
For some reason, some individuals are under the impression that he would make a good father- or mentor-figure for Harry Potter. This makes no sense because he hates Harry Potter's guts and lives a dangerous life as a Death Eater double agent, and thus would be totally unsuitable. It makes less sense for him to be paired with Harry as a lover, but this also happens.
Others make Snape wangst. They make him wangst about his past far harder than he ever did in the books or movies, and frankly this is annoying and bad; Snape never was a woobie, and he never should be.
PPC Missions Featuring This Character
Listed in chronological order according to when they take place on the HQ Standard Timeline, as near as can be determined.
- 'Two Worlds' (crossover with The Lord of the Rings), Agents Jay Thorntree and Acacia Byrd (DIC), August
- 'Dancing With Fireflies', Agents Aria and Polaris (DMS - HP), c. October
- 'The HP Series', Agents Magnolia and Myfanwy (DMS - HP), January
- 'Why You Shouldn't Kill Your Partner', Agents Lorac and Verra (DI), c. August
- 'By Those He Trusted', Agents Dee and Milask (DBS - HP) with Agent Taboo (DBS - MPreg), c. December
- 'Thou Shalt Not Suffer A Sue To Live', Agents Laburnum and Foxglove (DMS), June
- 'Subjugation' (incomplete; NSFW, Legendary Badfic), Agents Suicide and Diocletian (DMS), Gunny and Wayne (DMS), Rez and Flip (DF), and Jo and Shae (DMS), June
- 'The Veronica File' (incomplete), Agents Mithrenriene Rochmabriel and Isabel Stanton (DMS), Beth and Sam (DMS), Twitchy and WarPrincessSushi (DMS - HP) and Diana and Valdenia (DRD), October
- 'Family Ties', Agents Supernumerary and Ilraen-Aroline-Fothergill (DIC), November
- 'Threshold' (alternative link), Agents Mervin and Hyde (DMS - HP), March
- 'In which a Sue gives Phia and Brannie the Slip' (incomplete), Agents Branwen Beaton and Sophia Cole (DMFF), May
- 'Eris Discordia' (alternative link), Agents Mervin and Hyde (DMS - HP), November
- 'To the Moon', Part 1, Part 2, Agents Trojanhorse and Paddlebrains (DBS), June
- 'Manhood', Agents Trojanhorse and Paddlebrains (DBS), June
- 'And the Goddess Did Wangst, and Spake Annoyingly Unto the People', Agents Teek Virtanen and Crelmos (DF), August
- 'Extending the Family', Agent Oscar Henson (DBS - MPreg) with Agent Paddlebrains (DBS), December
- 'Rivalry Counseling with Jigsaw' (crossover with Saw), Agents Florestan and Eusabius (DIC), October
- '"The Making of a Queen," a.k.a. The raison d’être' (crossover with Labyrinth), Agents Mittens and the Radioactive Moss Creature (DF), October
- '"Smells of Rose" a.k.a. The Enemy of My Enemy' (crossover with Labyrinth), Agents James Vulpes and Saxo Cruore (DF), November
- 'A Girl Out of Time' (NSFW; crossover with Doctor Who), Agents Eledhwen and Christianne (DMS) with the Disentangler and the Agent (DIC), April
- 'Ordellya's Untimely End', Agents Rina Dives and Randa Roan (DMS), March
- 'When Stus Stalk Sues', Agents Rina Dives and Randa Roan (DMS), December
- 'Retribution', Agents Rina Dives and Randa Roan (DMS), January
- 'Harry+Draco+Snape? This Doesn't Add Up at All!', Agents Doom/Gloom and Carry Onin (DF), February
- The Girl Who Lived Series, Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Agents Rina Dives and Zeb (DMS), February–March
- 'But is She Goffik?', Agents Rina Dives and Zeb (DMS), April
- 'Snake Eyes', Agents Falchion and Velociripper (DF), May
- 'Little Miss Mary', Agents Rina Dives and Zeb (DMS), August
- 'Spring Cleaning', Agents Zeb and Dawn McKenna (DMS), September
- 'Irregular Apocalypse', Agents Desdendelle and the Librarian (DF) with Agent Aviator (DMS), October
- 'Family Ties', Agents Aviator and Zeb (DMS), November
- 'Babies, Babies Everywhere', Agents Aviator and Zeb (DMS) with Agent Dawn McKenna (DMS), June
- 'Hair of Slytherin', Agents Charlotte Webb and Ix (ESAS), October